If you experience problems concerning “extconf.rb”, you should try:http://phosphor-escence.blogspot.com/2010/12/if-you-fail-install-rmagick-on-mingw.html
fromhttp://www.waydotnet.com/blog/2010/02/rmagick-on-ruby-1-9-1-i386-mingw32-work-d/#comment-166014708
http://www.waydotnet.com/blog/2010/02/rmagick-on-ruby-1-9-1-i386-mingw32-work-d/#comment-317551623